Ocular muscles


There are a total of 6 extrinsic ocular muscles responsible for the manipulation of eye movements. The margin of the optic foramen, which is positioned along the rear of the orbital cavity, yields five of the six muscles involved.


There are 4 rectus muscles, each of which has been named aptly for its ability to manipulate the eye in the direction of its given name. Such as, the superior rectus manipulates the eyeball superiorly, the lateral rectus provides lateral manipulation, and so on with the inferior and the medial rectus muscles.

The superior and inferior obliques are responsible for manipulations involving their named direction, which rotate the eyeball on its axis.


Ocular Muscles
Image: Ocular Muscles

When the eyeballs are attempting to focus on objects which are close to the line of sight, the medial rectus on the right side contracts in unison with the medial rectus on the left side. Likewise, when the eyeballs want to view something to either side of the head, the medial rectus on one side works cohesively with the lateral rectus of the other eye, which enables both eyeballs to work as a unit.

The superior oblique muscle is designed with a pulley-like system inside the eye. It passes through the trochlea, which is a structural loop created from cartilage, before it is secured to the eyeball. The levator palpabrae superioris is the muscle which is found within the eye but is not part of the ocular muscle structure and in fact is not even attached to the eyeball. Rather, it attaches to the upper eyelid and is the primary muscle related to opening the eyes.
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